1 /*- 2 * Copyright (c) 1998 Michael Smith 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 /* 28 * The unified bootloader passes us a pointer to a preserved copy of 29 * bootstrap/kernel environment variables. We convert them to a 30 * dynamic array of strings later when the VM subsystem is up. 31 * 32 * We make these available through the kenv(2) syscall for userland 33 * and through getenv()/freeenv() setenv() unsetenv() testenv() for 34 * the kernel. 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_mac.h" 41 42 #include <sys/types.h> 43 #include <sys/param.h> 44 #include <sys/proc.h> 45 #include <sys/queue.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/priv.h> 50 #include <sys/kernel.h> 51 #include <sys/systm.h> 52 #include <sys/sysent.h> 53 #include <sys/sysproto.h> 54 #include <sys/libkern.h> 55 #include <sys/kenv.h> 56 57 #include <security/mac/mac_framework.h> 58 59 static MALLOC_DEFINE(M_KENV, "kenv", "kernel environment"); 60 61 #define KENV_SIZE 512 /* Maximum number of environment strings */ 62 63 /* pointer to the static environment */ 64 char *kern_envp; 65 static char *kernenv_next(char *); 66 67 /* dynamic environment variables */ 68 char **kenvp; 69 struct mtx kenv_lock; 70 71 /* 72 * No need to protect this with a mutex since SYSINITS are single threaded. 73 */ 74 int dynamic_kenv = 0; 75 76 #define KENV_CHECK if (!dynamic_kenv) \ 77 panic("%s: called before SI_SUB_KMEM", __func__) 78 79 int 80 kenv(td, uap) 81 struct thread *td; 82 struct kenv_args /* { 83 int what; 84 const char *name; 85 char *value; 86 int len; 87 } */ *uap; 88 { 89 char *name, *value, *buffer = NULL; 90 size_t len, done, needed, buflen; 91 int error, i; 92 93 KASSERT(dynamic_kenv, ("kenv: dynamic_kenv = 0")); 94 95 error = 0; 96 if (uap->what == KENV_DUMP) { 97 #ifdef MAC 98 error = mac_kenv_check_dump(td->td_ucred); 99 if (error) 100 return (error); 101 #endif 102 done = needed = 0; 103 buflen = uap->len; 104 if (buflen > KENV_SIZE * (KENV_MNAMELEN + KENV_MVALLEN + 2)) 105 buflen = KENV_SIZE * (KENV_MNAMELEN + 106 KENV_MVALLEN + 2); 107 if (uap->len > 0 && uap->value != NULL) 108 buffer = malloc(buflen, M_TEMP, M_WAITOK|M_ZERO); 109 mtx_lock(&kenv_lock); 110 for (i = 0; kenvp[i] != NULL; i++) { 111 len = strlen(kenvp[i]) + 1; 112 needed += len; 113 len = min(len, buflen - done); 114 /* 115 * If called with a NULL or insufficiently large 116 * buffer, just keep computing the required size. 117 */ 118 if (uap->value != NULL && buffer != NULL && len > 0) { 119 bcopy(kenvp[i], buffer + done, len); 120 done += len; 121 } 122 } 123 mtx_unlock(&kenv_lock); 124 if (buffer != NULL) { 125 error = copyout(buffer, uap->value, done); 126 free(buffer, M_TEMP); 127 } 128 td->td_retval[0] = ((done == needed) ? 0 : needed); 129 return (error); 130 } 131 132 switch (uap->what) { 133 case KENV_SET: 134 error = priv_check(td, PRIV_KENV_SET); 135 if (error) 136 return (error); 137 break; 138 139 case KENV_UNSET: 140 error = priv_check(td, PRIV_KENV_UNSET); 141 if (error) 142 return (error); 143 break; 144 } 145 146 name = malloc(KENV_MNAMELEN, M_TEMP, M_WAITOK); 147 148 error = copyinstr(uap->name, name, KENV_MNAMELEN, NULL); 149 if (error) 150 goto done; 151 152 switch (uap->what) { 153 case KENV_GET: 154 #ifdef MAC 155 error = mac_kenv_check_get(td->td_ucred, name); 156 if (error) 157 goto done; 158 #endif 159 value = getenv(name); 160 if (value == NULL) { 161 error = ENOENT; 162 goto done; 163 } 164 len = strlen(value) + 1; 165 if (len > uap->len) 166 len = uap->len; 167 error = copyout(value, uap->value, len); 168 freeenv(value); 169 if (error) 170 goto done; 171 td->td_retval[0] = len; 172 break; 173 case KENV_SET: 174 len = uap->len; 175 if (len < 1) { 176 error = EINVAL; 177 goto done; 178 } 179 if (len > KENV_MVALLEN) 180 len = KENV_MVALLEN; 181 value = malloc(len, M_TEMP, M_WAITOK); 182 error = copyinstr(uap->value, value, len, NULL); 183 if (error) { 184 free(value, M_TEMP); 185 goto done; 186 } 187 #ifdef MAC 188 error = mac_kenv_check_set(td->td_ucred, name, value); 189 if (error == 0) 190 #endif 191 setenv(name, value); 192 free(value, M_TEMP); 193 break; 194 case KENV_UNSET: 195 #ifdef MAC 196 error = mac_kenv_check_unset(td->td_ucred, name); 197 if (error) 198 goto done; 199 #endif 200 error = unsetenv(name); 201 if (error) 202 error = ENOENT; 203 break; 204 default: 205 error = EINVAL; 206 break; 207 } 208 done: 209 free(name, M_TEMP); 210 return (error); 211 } 212 213 /* 214 * Setup the dynamic kernel environment. 215 */ 216 static void 217 init_dynamic_kenv(void *data __unused) 218 { 219 char *cp; 220 int len, i; 221 222 kenvp = malloc((KENV_SIZE + 1) * sizeof(char *), M_KENV, 223 M_WAITOK | M_ZERO); 224 i = 0; 225 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 226 len = strlen(cp) + 1; 227 if (i < KENV_SIZE) { 228 kenvp[i] = malloc(len, M_KENV, M_WAITOK); 229 strcpy(kenvp[i++], cp); 230 } else 231 printf( 232 "WARNING: too many kenv strings, ignoring %s\n", 233 cp); 234 } 235 kenvp[i] = NULL; 236 237 mtx_init(&kenv_lock, "kernel environment", NULL, MTX_DEF); 238 dynamic_kenv = 1; 239 } 240 SYSINIT(kenv, SI_SUB_KMEM, SI_ORDER_ANY, init_dynamic_kenv, NULL); 241 242 void 243 freeenv(char *env) 244 { 245 246 if (dynamic_kenv) 247 free(env, M_KENV); 248 } 249 250 /* 251 * Internal functions for string lookup. 252 */ 253 static char * 254 _getenv_dynamic(const char *name, int *idx) 255 { 256 char *cp; 257 int len, i; 258 259 mtx_assert(&kenv_lock, MA_OWNED); 260 len = strlen(name); 261 for (cp = kenvp[0], i = 0; cp != NULL; cp = kenvp[++i]) { 262 if ((strncmp(cp, name, len) == 0) && 263 (cp[len] == '=')) { 264 if (idx != NULL) 265 *idx = i; 266 return (cp + len + 1); 267 } 268 } 269 return (NULL); 270 } 271 272 static char * 273 _getenv_static(const char *name) 274 { 275 char *cp, *ep; 276 int len; 277 278 for (cp = kern_envp; cp != NULL; cp = kernenv_next(cp)) { 279 for (ep = cp; (*ep != '=') && (*ep != 0); ep++) 280 ; 281 if (*ep != '=') 282 continue; 283 len = ep - cp; 284 ep++; 285 if (!strncmp(name, cp, len) && name[len] == 0) 286 return (ep); 287 } 288 return (NULL); 289 } 290 291 /* 292 * Look up an environment variable by name. 293 * Return a pointer to the string if found. 294 * The pointer has to be freed with freeenv() 295 * after use. 296 */ 297 char * 298 getenv(const char *name) 299 { 300 char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1]; 301 char *ret, *cp; 302 int len; 303 304 if (dynamic_kenv) { 305 mtx_lock(&kenv_lock); 306 cp = _getenv_dynamic(name, NULL); 307 if (cp != NULL) { 308 strcpy(buf, cp); 309 mtx_unlock(&kenv_lock); 310 len = strlen(buf) + 1; 311 ret = malloc(len, M_KENV, M_WAITOK); 312 strcpy(ret, buf); 313 } else { 314 mtx_unlock(&kenv_lock); 315 ret = NULL; 316 } 317 } else 318 ret = _getenv_static(name); 319 return (ret); 320 } 321 322 /* 323 * Test if an environment variable is defined. 324 */ 325 int 326 testenv(const char *name) 327 { 328 char *cp; 329 330 if (dynamic_kenv) { 331 mtx_lock(&kenv_lock); 332 cp = _getenv_dynamic(name, NULL); 333 mtx_unlock(&kenv_lock); 334 } else 335 cp = _getenv_static(name); 336 if (cp != NULL) 337 return (1); 338 return (0); 339 } 340 341 /* 342 * Set an environment variable by name. 343 */ 344 int 345 setenv(const char *name, const char *value) 346 { 347 char *buf, *cp, *oldenv; 348 int namelen, vallen, i; 349 350 KENV_CHECK; 351 352 namelen = strlen(name) + 1; 353 if (namelen > KENV_MNAMELEN) 354 return (-1); 355 vallen = strlen(value) + 1; 356 if (vallen > KENV_MVALLEN) 357 return (-1); 358 buf = malloc(namelen + vallen, M_KENV, M_WAITOK); 359 sprintf(buf, "%s=%s", name, value); 360 361 mtx_lock(&kenv_lock); 362 cp = _getenv_dynamic(name, &i); 363 if (cp != NULL) { 364 oldenv = kenvp[i]; 365 kenvp[i] = buf; 366 mtx_unlock(&kenv_lock); 367 free(oldenv, M_KENV); 368 } else { 369 /* We add the option if it wasn't found */ 370 for (i = 0; (cp = kenvp[i]) != NULL; i++) 371 ; 372 373 /* Bounds checking */ 374 if (i < 0 || i >= KENV_SIZE) { 375 free(buf, M_KENV); 376 mtx_unlock(&kenv_lock); 377 return (-1); 378 } 379 380 kenvp[i] = buf; 381 kenvp[i + 1] = NULL; 382 mtx_unlock(&kenv_lock); 383 } 384 return (0); 385 } 386 387 /* 388 * Unset an environment variable string. 389 */ 390 int 391 unsetenv(const char *name) 392 { 393 char *cp, *oldenv; 394 int i, j; 395 396 KENV_CHECK; 397 398 mtx_lock(&kenv_lock); 399 cp = _getenv_dynamic(name, &i); 400 if (cp != NULL) { 401 oldenv = kenvp[i]; 402 for (j = i + 1; kenvp[j] != NULL; j++) 403 kenvp[i++] = kenvp[j]; 404 kenvp[i] = NULL; 405 mtx_unlock(&kenv_lock); 406 free(oldenv, M_KENV); 407 return (0); 408 } 409 mtx_unlock(&kenv_lock); 410 return (-1); 411 } 412 413 /* 414 * Return a string value from an environment variable. 415 */ 416 int 417 getenv_string(const char *name, char *data, int size) 418 { 419 char *tmp; 420 421 tmp = getenv(name); 422 if (tmp != NULL) { 423 strlcpy(data, tmp, size); 424 freeenv(tmp); 425 return (1); 426 } else 427 return (0); 428 } 429 430 /* 431 * Return an integer value from an environment variable. 432 */ 433 int 434 getenv_int(const char *name, int *data) 435 { 436 quad_t tmp; 437 int rval; 438 439 rval = getenv_quad(name, &tmp); 440 if (rval) 441 *data = (int) tmp; 442 return (rval); 443 } 444 445 /* 446 * Return an unsigned integer value from an environment variable. 447 */ 448 int 449 getenv_uint(const char *name, unsigned int *data) 450 { 451 quad_t tmp; 452 int rval; 453 454 rval = getenv_quad(name, &tmp); 455 if (rval) 456 *data = (unsigned int) tmp; 457 return (rval); 458 } 459 460 /* 461 * Return a long value from an environment variable. 462 */ 463 int 464 getenv_long(const char *name, long *data) 465 { 466 quad_t tmp; 467 int rval; 468 469 rval = getenv_quad(name, &tmp); 470 if (rval) 471 *data = (long) tmp; 472 return (rval); 473 } 474 475 /* 476 * Return an unsigned long value from an environment variable. 477 */ 478 int 479 getenv_ulong(const char *name, unsigned long *data) 480 { 481 quad_t tmp; 482 int rval; 483 484 rval = getenv_quad(name, &tmp); 485 if (rval) 486 *data = (unsigned long) tmp; 487 return (rval); 488 } 489 490 /* 491 * Return a quad_t value from an environment variable. 492 */ 493 int 494 getenv_quad(const char *name, quad_t *data) 495 { 496 char *value; 497 char *vtp; 498 quad_t iv; 499 500 value = getenv(name); 501 if (value == NULL) 502 return (0); 503 iv = strtoq(value, &vtp, 0); 504 if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) { 505 freeenv(value); 506 return (0); 507 } 508 switch (vtp[0]) { 509 case 't': case 'T': 510 iv *= 1024; 511 case 'g': case 'G': 512 iv *= 1024; 513 case 'm': case 'M': 514 iv *= 1024; 515 case 'k': case 'K': 516 iv *= 1024; 517 case '\0': 518 break; 519 default: 520 freeenv(value); 521 return (0); 522 } 523 *data = iv; 524 freeenv(value); 525 return (1); 526 } 527 528 /* 529 * Find the next entry after the one which (cp) falls within, return a 530 * pointer to its start or NULL if there are no more. 531 */ 532 static char * 533 kernenv_next(char *cp) 534 { 535 536 if (cp != NULL) { 537 while (*cp != 0) 538 cp++; 539 cp++; 540 if (*cp == 0) 541 cp = NULL; 542 } 543 return (cp); 544 } 545 546 void 547 tunable_int_init(void *data) 548 { 549 struct tunable_int *d = (struct tunable_int *)data; 550 551 TUNABLE_INT_FETCH(d->path, d->var); 552 } 553 554 void 555 tunable_long_init(void *data) 556 { 557 struct tunable_long *d = (struct tunable_long *)data; 558 559 TUNABLE_LONG_FETCH(d->path, d->var); 560 } 561 562 void 563 tunable_ulong_init(void *data) 564 { 565 struct tunable_ulong *d = (struct tunable_ulong *)data; 566 567 TUNABLE_ULONG_FETCH(d->path, d->var); 568 } 569 570 void 571 tunable_quad_init(void *data) 572 { 573 struct tunable_quad *d = (struct tunable_quad *)data; 574 575 TUNABLE_QUAD_FETCH(d->path, d->var); 576 } 577 578 void 579 tunable_str_init(void *data) 580 { 581 struct tunable_str *d = (struct tunable_str *)data; 582 583 TUNABLE_STR_FETCH(d->path, d->var, d->size); 584 } 585